Some thoughts on this...
ALT is a liver specific indicator and the value of the enzymes is proportional to the number of hepatocytes involved. Thus the higher the number, the more of the liver that is involved. Unfortunately, ALT does not give us information to the severity or cause of the liver damage. ALP is a bit less specific but also common with any inflammation or damage of the liver.
Radiographs (X-Rays) and Ultrasound. What do they mean?
Radiographs are an easy way to get a peek at the silhouette of the liver. It is good for livers that are very, very small or very, very big. Also it is a great way to look at other areas of the abdomen. Overall, radiographs are a tad limited with regard to the liver. Ultrasound will look at the inside of the liver in cross sectional views. It is better for look for abnormalities of architexture and can help pinpoint where a biopsy should be taken. Ultimately a biopsy or fine needle aspirate is typically needed to get a full answer. Additionally, depending upon the demographics, certain parasites should be evaluated for before.
I agree with MaxaLisa with regard to a concern about alcohol based tinctures.
With regard to Country Life's "Liver Support Factors, upon looking at the active ingredients, I do not see SAMe as a part of this. SAMe is a great supplement that can help with liver support. As these tablets are enteric coated and do not work if split or crushed, for small dogs I usually recommend the veterinary formation which could be used in conjunction with this recommendation by MaxaLisa. SAMe is one of the best liver supplements out there. Sylmarin and zinc (both in the Country Life's) are also very common and have scientific support in their general use for dogs with certain types of liver disease. I do not have any direct experience with Country Life's Liver Support Factors so have no further comment on it other than there is some anecdotal support for some of the ingredients within it.
In a diet, I would recommend a diet that has proper levels of EPA, DHA and Omega 3:6 ratio. This could help with inflammation and is just always a good idea. Controlled copper levels can be important with many types of liver issues. As always, I recommend a diet that does not have overly high levels of calcium, phosphorus or sodium (as many, many pet foods do). Foods from companies that are trusted and willing to provide complete AAFCO testing rather than just formulation is also important. Finally proper carnitine supplementation within the diet can help with hepatic function.
I hope this helps.